This proposal argues that loneliness among adolescents is an extremely widespread and uniformly painful condition. Evidence is given to indicate that in attempting to avoid the pain of lonesliness many persons adopt extremely dysfunctional escape routes: drug abuse, alcohol, suicide, further withdrawal, etc. The present proposal would examine the extent of different types of loneliness amongst adolescents, and would analyse hypothesized theories and causes of loneliness. Three major forms of loneliness would be analysed: social isolation, emotional isolation and the loneliness of lack of purpose and goals. The general epidemiology of loneliness in the youth population would be examined. Extensive bivariate and multivariate analyses would be conducted on the social and psychological correlates of these forms of loneliness. The proposal involves purely secondary analysis of existing data sets which had the purpose of examining the social psychological development of youth. Aside from the theoretical testing and epidemiological work, an overall taxonomy of youth would be created in terms of loneliness and its predictors. High risk groups of youth would be identified.